Maillard Chemistry in Clouds and Aqueous Aerosol As a Source of Atmospheric Humic-Like Substances

• DOI: 10.1021/acs.est.6b00909
• Publication Date: 2016-05-26T17:05:42Z
• Authors: Lelia N. Hawkins; Amanda N. Lemire; Melissa M. Galloway; Ashley L. Corrigan; Jacob J. Turley; Brenna M. Espelien; David O. De Haan
• Keywords: Atmospheric chemistry

The reported optical, physical, and chemical properties of aqueous Maillard reaction mixtures small aldehydes (glyoxal, methylglyoxal, glycolaldehyde) with ammonium sulfate amines are compared those extracts ambient aerosol (water-soluble organic carbon, WSOC) the humic-like substances (HULIS) fraction WSOC. Using a combination new previously published measurements, we examine fluorescence, X-ray absorbance, UV/vis, IR spectra, complex refractive indices, 1H 13C NMR thermograms, electrospray ionization mass surface activity, hygroscopicity. Atmospheric WSOC HULIS encompass range properties, but in almost every case aldehyde-amine squarely within this range. Notable exceptions higher UV/visible absorbance wavelength dependence (Angström coefficients) observed for methylglyoxal mixtures, lack activity glyoxal N/C ratios products relative to atmospheric extracts. overall similarities consistent with, not demonstrative of, chemistry being significant secondary source HULIS. However, limits strength ≤50% HULIS, assuming that other sources incorporate only negligible quantities nitrogen.